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This invention relates to an interactively modulable support apparatus, such as a mattress, having a layer of pressure adjustable self-inflating, open-cell, flexible polyurethane foam core and a layer of mattress spring coils. Both layers are independently adjustable as to softness/hardness, but also interactively modulable in the way that adjustment of the foam core layer modifies the characteristics of the coil spring layer.
This invention is a multiple layer combination mattress. One or more layers are self-inflating elastomeric open-cell polyurethane foam and another layer is a section having mechanical coil springs therein. Both layers are individually, as well as interactively adjustable as to their hardness and softness (indentation force deflectionxe2x80x94IFD) and support (density).
Various designs have been made in the past to control the hardness, softness, and support firmness of foam layers within a mattress by using different zones of foam layers for different parts of the body, or by controlling the firmness or responsiveness of coil springs in mattresses, but to control both layers so that they can be adjusted by the user, foam and coil independently and interactively in one mattress, has not been achieved and is not found in the prior art in the manner of this invention.
U.S. Pat. No. 2,779,034 to Arpin discloses a firmness adjustment for mattresses involving a standard coil spring mattress wherein standard coil springs are enclosed by a loosely fitting airtight cover. A vacuum pump can be applied to the cover in order to compress the coil springs within the mattress to make them harder. Although the disclosure of Arpin mentions xe2x80x98rubber foamxe2x80x99 or similar material, it does not involve any open-cell, self-inflating foam varieties, nor does Arpin teach that the respective density and IFD values, which are determined by the cellular structure of the foam or foam-like material he may have had in mind, may be modulated to result in a softer or harder mattress without sacrificing support-firmness in the process of multiple comfort adjustments. The present invention, however, modulates the foam core layers"" characteristics in a way as to bring pressure resulting from that modulation to bear onto the coil spring layer, thus interactively and incrementally increasing this layer""s firmness in a predetermined range of modulation, whereas Arpin only applies a vacuum to the coil spring section to increase indentation force deflection (increasing firmness) of the coil spring layer.
A further fundamental difference lies in the fact that the present teaching does the opposite and still at the same time increases support. This effect is achieved by utilization of the properties of special foam material which is manufactured and applied expressly for the purpose of modulating indentation force deflection and density from maximum firm state to a chosen state of softness without weakening the desirable effect of high support.
U.S. Pat. No. 3,611,524 illustrates a method of assembling a mattress. The disclosure involves a ready-made mattress either of the coil spring type or foam type which is initially wrapped in an airtight sheet of plastic and a vacuum pump is applied to the wrapped combination and the coil spring mattress or the foam mattress will collapse under the force of the vacuum and either of the collapsed forms can now be inserted into a finishing cover. Once the vacuum in either mattress is released, either one of the mattresses will expand to snugly fit within the outer covering. This disclosed invention is designed for a one time use only. Moreover, there is a teaching within this reference that the preliminary wrapping sheet should be removed. In contrast to this, the invention at hand can be used time and time again to adjust the various levels of firmness desired. No disclosure within U.S. Pat. No. 3,611,524 is made that the aim is to adjust comfort levels. A manufacturing process is described wherein a filling material is reduced in volume by removing air from it to be able to quickly and efficiently introduce it in a sleeve before it has time to expand again. This method is now used worldwide by upholsterers and furniture manufacturers.
U.S. Pat. No. 3,872,525 to Lea discloses a camping mat using a self-inflating foam within an airtight outer cover that is vulcanized to the inner foam layer. The air within can be removed by compressing the structure whereby the foam layer collapses, allowing the mat to be rolled up into a compact package. The firmness (IFD) or density can not be modulated freely because of the thinness and light weight of the foam layer used in camping mats. Furthermore, compressing the camping mat by hand does not expel the air uniformly from all the foam cells but only in the area being compressed by hand. Clearly, modulating comfort and firmness were not in the mind of the inventors, but a method of decreasing the mat""s volume for easy packing and transport
The invention at hand uses a thicker, higher density foam core to start with, which can be adjusted infinitely to multiple levels of firmness and support not found in the prior art and thus adjusts the coil spring layer accordingly. Its priority lies with comfort modulation and should not be considered a method of packaging a camping mat into a small size to be carried in a backpack.
U.S. Pat. No. 4,025,974 discloses a self-inflating air mattress/mat including an airtight flexible envelope which encloses a core of resilient, open cell, lightweight foam material, substantially the entire upper and lower portions of which are bonded to the envelope. Heated platens are applied to this lay-up, followed by creating a vacuum in the interior, cooling and pressurizing the assembly, then moderately pressurizing the whole. The invention at hand does not bond any outer coverings to the enclosed foam layer. On the contrary, this invention uses a device to distance the foam from the cover in order to enhance airflow and to prevent the foam or cover from obstructing the valve when air is drawn out of the mattress or when it is self-inflating.
Again, the aim of the teaching in this patent is to compress the mat for easy transport in a backpack. Furthermore, there is no indication of a further objective to intentionally modulate the foam density or IFD within the foam core with the aid of a vacuum to obtain multiple levels of firmness and support. Lastly, Lea proposes to utilize foam types with a density not greater than 1.2 or 1.5 in their original state. No mention is made of interactivity with other mattress layers.
U.S. Pat. No. 4,711,067 teaches the packaging of a mattress wherein the thickness of an elastic structure of a mattress is reduced. An extra cover is fitted over the mattress which is fitted over the structure of a pressing device. This procedure will completely flatten the mattress for roll-up. There is no disclosure to control any comfort level or to apply a vacuum pump to do so, nor of any interactivity with other mattress layers.
U.S. Pat. No. 4,944,060 illustrates a mattress having a plurality of discrete, air permeable cells which are to some extent hydrophobic. In opposition to the invention at hand there is no block of a foam core of any kind, no covering encasing or envelope and there is no teaching of complete air evacuation, nor mention of interactivity with other mattress layers.
The invention at hand does not use any pressurized air but a vacuum only, whereas the above art teaches the opposite, namely pressurization of a chamber to increase the hardness of the support surface. If air were allowed to escape from the chamber, the support surface would collapse and cause a hammock effect.
In the invention at hand interactive foam core never exhibits a collapsing hammock effect when air is removed from within the foam cells, but adjusts to the body""s pressure points locally as density within the foam core increases to offer more support, and exerts less pressure on the adjacent coil spring layer to also increase softness and comfort.
U.S. Pat. No. 5,947,168 illustrates a method and apparatus for rapidly deflating and substantially emptying an inflatable air chamber, the chamber being a mattress. This disclosure does not involve any self-inflating alternating density polyurethane foam and therefore, is not pertinent to the invention at hand.
U.S. Pat. No. 6,098,378 discloses a method of packaging a single mattress to a small size to be conveniently carried. In this method and apparatus, the foam mattress is compressed to fit into a hard container for shipment. At the point of sale, the mattress is extracted and expands to its original shape. This appears as a one time use only and there is no teaching of adjusting the comfort level of a user through modulation of pressure.
Furthermore, none of the above prior art teachings take advantage of the expanding force of a self-inflating foam core that while it is in the process of expanding, compresses an adjacent core and modifies the properties of that core.
The invention results from the realization that a combination of a self-inflating, adjustable density, variable IFD, open-cell flexible polyurethane foam core with a mattress layer having coils therein greatly enhances the versatility of this mattress combination, offering great variety in adjustable levels of comfort.
The invention teaches how the Indentation Force Deflection (IFD) and density properties of a certain quality range of flexible open-cell polyurethane foam can be modulated by removing some of the air from within the foam cells and altering the cellular structure of the foam core. High density foam is more expensive (such as visco-elastic foam). They provide great comfort. The focal teaching of this invention is how to modulate a comparatively inexpensive, lower density foam to feel similar to a high density foam, and attain support and comfort characteristics of a higher density, more expensive foam, through layer interactivity between foam and traditional coil spring arrangements, without locking the user into one fixed comfort level, but give him a wide choice between very hard and very soft comfort.
IFD and density modulation are achieved by manipulating flexible polyurethane foam or material of similar characteristics. This art teaches that this material is fashioned in a particular form and that it has to be of a molecular composition as to permit the extraction of air in the alveolate structure in a uniform manner, thus increasing material density equally uniformly. A further specialty of this material is that, by virtue of its structure, particular manufacturing and finishing processes, it affords in its low IFD number modulated state commensurably higher firmness stability, heretofore only associated with foam or similar material of a very much higher density number. Finally, it is much lighter in weight than the latter and can be reduced in size and volume for easy transport and storage.
This teaching also involves different reversible mattress combinations that one or more users may adjust differentially and individually to his or her liking, depending which side of the bed they choose to recline upon (left or right side of the bed, or the reverse surface). It also demonstrates that many incremental levels of firmness or softness may be achieved by one piece of foam as it changes from low density and high IFD to a high density low IFD more desirable foam, as well as when it interacts with other adjacent coil cores, changing their particular IFD and firmness characteristics.
In the present invention a custom fan-style vacuum pump that draws air out of the foam core to double its density and to reduce its IFD value considerably. After only a few seconds of the pump""s operation the foam feels like a high density, resilient foam with an IFD of under 20, supported by an equally modulated coil spring layer with adjusted softness. Since the vacuum pump comes equipped with variable speed and remote control memory settings this transformation occurs at the speed and in increments desired by the user.
The experiments conducted entailed a user reclining on the foam/coil spring original firm configuration and subsequently adjusting the density and IFD settings within the foam core. It was observed that the user""s heaviest parts of the body sank into the foam and were contoured progressively as the density increased and the IFD decreased. Thanks to this functionality, as well as the underlying coil spring layer, no collapsing or hammock effect took place within the mattress, which was lighter and thinner than any other mattresses using a different technologyxe2x80x94reduction in weight, bulk and cost being industry priority requirements for new mattress technology.
This invention takes advantage of the adjustability of the self-inflating foam core as to comfort and also uses said adjustability to change the properties of the coil mattress above or below the foam mattress core. The structure of this combination allows the mattress cores to be used in two horizontal juxtaposed orientations. Either the foam part of the mattress faces upwards or the coil part of the mattress faces upwards. This is decided by the user of the mattress. In particular, air can be exhausted from the foam part of the mattress combination uniformly with the aid of a vacuum pump, which results in increasing the density of the foam core and decreasing the IFD within the core for a softer feeling foam core with more support. Since the coil core and the foam core are trapped within an airtight outer chamber the properties of said coil core will change as the foam core expands or contracts. Moreover, and like Arpin""s teaching, the coil core combination of the mattress combination may additionally be compressed by evacuating the air of the chamber containing the coils which would result in increasing the hardness of that part of the mattress but would also affect the adjacent foam core. This interactivity in adjustability contributes greatly to the versatility of such a mattress combination.
The basic configuration of this invention, which comes in a broad variety of combinations between foam and spring coil cores and compartments, takes the form of a mattress, as one example of among a large number of support apparatuses, with at least three chambers each containing a valve communicably extending to the outside air. The valves contribute greatly to the versatility of the invention as will be explained further.
The first hermetically sealed chamber is an overall outer enclosure of the total mattress combination and will trap and compress the other two chambers if evacuated of air. A second chamber contains an assembly of coil springs, while a third chamber contains a core of self-inflating polyurethane foam. As mentioned above, the first layer encompasses the second and third layers tightly. If the chamber of self-inflating foam is allowed to inflate, it compresses the coil chamber trapped above or below it. By compressing the coils either directly by evacuating air with a vacuum from the coil chamber, or by compressing the coil chamber with the rising force of the self-inflating foam chamber, the coil portion of the mattress becomes firmer. On the other hand, if some air was evacuated from the foam chamber the coil portion would relax and feel softer.